HELP, mods made care less HP
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 2,916
Likes: 1
From: West Palm Beach Florida
HELP, mods made care less HP
I have 2002 c5 & completely stock was dyno at 311 rwhp.
I then added magnaflow catbacks with x pipe & resonators, exhaust & added short air dual cone intake.
My car was Dyno at 279, I took it to a second place to have done again & after 2 hrs, he could only get 279rwhp.
What happened
Dyno print outs:
http://i200.photobucket.com/albums/a...tte/Dyno_2.jpg
http://i200.photobucket.com/albums/a...tte/Dyno_1.jpg
I then added magnaflow catbacks with x pipe & resonators, exhaust & added short air dual cone intake.
My car was Dyno at 279, I took it to a second place to have done again & after 2 hrs, he could only get 279rwhp.
What happened
Dyno print outs:
http://i200.photobucket.com/albums/a...tte/Dyno_2.jpg
http://i200.photobucket.com/albums/a...tte/Dyno_1.jpg
Racer
Joined: Feb 2006
Posts: 273
Likes: 1
From: Columbia Maryland
Were they different kinds of dynos? Some are pre loaded with resistance and give differnet values by almost 15% (that number may be off, but it is significant)
edit- I just saw your pictures, go back and get it tested at the mustang dyno if you want to compare results. They are 2 different types of dynos.
edit- I just saw your pictures, go back and get it tested at the mustang dyno if you want to compare results. They are 2 different types of dynos.
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 2,916
Likes: 1
From: West Palm Beach Florida
same place
I had it Dyno at the same place 2 times. he came up with 311 stock
& 270 something, after mods.
I then took to a second place, & still came up with 270's.
& 270 something, after mods.
I then took to a second place, & still came up with 270's.
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
its all so easy but you need to think ahead....
sounds like in this case, GM knows something that your after mod companys don't, well not really lol...To ease your pain a little...from what I have read and heard, the mods you do must be done in like a package type of deal.
In other words your car was setup stock and everything worked great!
Now you have messed with that by changing something. (exhaust and intake) You now need to do something else to complement what you have done.....the exhaust and intake now is breathing easier. So maybe you need to adjust the spark and fuel? ahhhemmmmm I sense a retune is in order to make those mods you have done come to life!
my 02....get it retuned buddy!
In other words your car was setup stock and everything worked great!
Now you have messed with that by changing something. (exhaust and intake) You now need to do something else to complement what you have done.....the exhaust and intake now is breathing easier. So maybe you need to adjust the spark and fuel? ahhhemmmmm I sense a retune is in order to make those mods you have done come to life!
my 02....get it retuned buddy!
Melting Slicks
Joined: Jul 2004
Posts: 2,567
Likes: 1
From: Edmond, OK...One of the first rules of online forums: If you don't like what is said but can't refute it, attack the poster.
Where do you live? Someone will be able to suggest a place to get a tune.
jeff
Burning Brakes
Joined: Jan 2004
Posts: 1,202
Likes: 2
From: Bergen County NJ
sounds like in this case, GM knows something that your after mod companys don't, well not really lol...To ease your pain a little...from what I have read and heard, the mods you do must be done in like a package type of deal.
In other words your car was setup stock and everything worked great!
Now you have messed with that by changing something. (exhaust and intake) You now need to do something else to complement what you have done.....the exhaust and intake now is breathing easier. So maybe you need to adjust the spark and fuel? ahhhemmmmm I sense a retune is in order to make those mods you have done come to life!
my 02....get it retuned buddy!
In other words your car was setup stock and everything worked great!
Now you have messed with that by changing something. (exhaust and intake) You now need to do something else to complement what you have done.....the exhaust and intake now is breathing easier. So maybe you need to adjust the spark and fuel? ahhhemmmmm I sense a retune is in order to make those mods you have done come to life!
my 02....get it retuned buddy!
You need to take it to a qualified tuner who has experience tuning Vettes and the right tuning software (e.g., EFI Live) in order to optmize your new mods. Please report back your new dyno numbers - hopefully he can get you an extra 20 hp above and beyond the stock 311 hp (unless by "exhaust" you meant headers in addition to your catbacks, in which case your ought to get more).
Good luck
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Drifting
Joined: Sep 2002
Posts: 1,614
Likes: 7
From: South Florida
You should get some power from the air filters. Are they new or used. If used are they cleaned and oiled correctly?
Also, did you dyno the same day under the same condtions? Your engine power will change based on barrometric pressure, humidity, temperature, fuel, etc.
swap the air filter out and re-dyno. Does the power go up? You shouldn't need a tune for just an airfilter. After 100 miles your car compter will adjust. That said, a tune can increase your power and there are a lot of options out there. I'd do a couple other mods before going to a tune...or you'll need to retune it if\when you change something big.
Drifting
Joined: Jan 2000
Posts: 1,660
Likes: 9
From: Charlotte, NC
In short, this is quite surprising.
I doubt most people on the board would expect to see a car with those mods do anything but increase in power.
I agree with the above post, take it to be dynod again and then swap the stock intake back on. If the power stays down, then you know it isn't the mods that are hurting the power, probably the weather (assuming your dyno doesn't already correct for that) or something else. You graph looks smooth and you A/F mixture looks decent. Wonder if you're losing any timing?
This is really weird.
I doubt most people on the board would expect to see a car with those mods do anything but increase in power.
I agree with the above post, take it to be dynod again and then swap the stock intake back on. If the power stays down, then you know it isn't the mods that are hurting the power, probably the weather (assuming your dyno doesn't already correct for that) or something else. You graph looks smooth and you A/F mixture looks decent. Wonder if you're losing any timing?
This is really weird.
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 2,916
Likes: 1
From: West Palm Beach Florida
mmmmm
The car was tuned at stock ($250.00) 303(base) to 311rwhp
The car had mods & retuned ($250.00) 270's rwhp
Both of the above at same place, weeks apart.
Went to another place ($300.00) he retuned & best was 279rwhp.
All Mods were brand new in the box
I didn't put oil on air filter, this is not type for oil,
it is the Y with dual cones the size of mmmmm, well real big
The car had mods & retuned ($250.00) 270's rwhp
Both of the above at same place, weeks apart.
Went to another place ($300.00) he retuned & best was 279rwhp.
All Mods were brand new in the box
I didn't put oil on air filter, this is not type for oil,
it is the Y with dual cones the size of mmmmm, well real big
Last edited by lil vette; Jun 14, 2007 at 01:26 PM. Reason: add on to
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
You are not really giving us enough information to go on
1.. Transmission type.. A4 or MN6? (A4 trans have more parasitic hp loss than Mn6)
2.. What type Model/make of Dyno was used?.. Different dynos make different numbers
3. Dyno settings? What were they?.. SAE Standard,, Uncorrrected, Corrected,, something else?? Need to know this.. These settings make a big difference..
I've learned to take dyno results with a grain of salt.. I've seen numbers on bone stock C5s from 270-340 rwhp on this Forum,due to the above information.. Stick with the same shop, same settings (dyno SAE corrected), same person to do your tests after mods. 270rwhp would be about right with uncorrected numbers on a hot humid day with a high elevation... 320rwhp would be about right on a cold dry day at sea level... Make sure your shop sticks with SAE Corrected settings.
1.. Transmission type.. A4 or MN6? (A4 trans have more parasitic hp loss than Mn6)
2.. What type Model/make of Dyno was used?.. Different dynos make different numbers
3. Dyno settings? What were they?.. SAE Standard,, Uncorrrected, Corrected,, something else?? Need to know this.. These settings make a big difference..
I've learned to take dyno results with a grain of salt.. I've seen numbers on bone stock C5s from 270-340 rwhp on this Forum,due to the above information.. Stick with the same shop, same settings (dyno SAE corrected), same person to do your tests after mods. 270rwhp would be about right with uncorrected numbers on a hot humid day with a high elevation... 320rwhp would be about right on a cold dry day at sea level... Make sure your shop sticks with SAE Corrected settings.
Last edited by David426; Jun 14, 2007 at 01:56 PM.
